[PATCH 4.17 336/336] ACPICA: AML Parser: ignore control method status in module-level code

[Greg Kroah-Hartman]

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Erik Schmauss <erik.schmauss@xxxxxxxxx>

commit 460a53106ac39b74625d1104d9a113e0f3716c18 upstream.

Previous change in the AML parser code blindly set all non-successful
dispatcher statuses to AE_OK. That approach is incorrect, though,
because successful control method invocations from module-level
return AE_CTRL_TRANSFER. Overwriting AE_OK to this status causes the
AML parser to think that there was no return value from the control
method invocation.

Fixes: 92c0f4af386 (ACPICA: AML Parser: ignore dispatcher error status during table load)
Reported-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Tested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Tested-by: Oleksandr Natalenko <oleksandr@xxxxxxxxxxxxxx>
Signed-off-by: Erik Schmauss <erik.schmauss@xxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/acpi/acpica/psloop.c |   19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

--- a/drivers/acpi/acpica/psloop.c
+++ b/drivers/acpi/acpica/psloop.c
@@ -709,15 +709,20 @@ acpi_status acpi_ps_parse_loop(struct ac
 			} else
 			    if ((walk_state->
 				 parse_flags & ACPI_PARSE_MODULE_LEVEL)
+				&& status != AE_CTRL_TRANSFER
 				&& ACPI_FAILURE(status)) {
 				/*
-				 * ACPI_PARSE_MODULE_LEVEL means that we are loading a table by
-				 * executing it as a control method. However, if we encounter
-				 * an error while loading the table, we need to keep trying to
-				 * load the table rather than aborting the table load. Set the
-				 * status to AE_OK to proceed with the table load. If we get a
-				 * failure at this point, it means that the dispatcher got an
-				 * error while processing Op (most likely an AML operand error.
+				 * ACPI_PARSE_MODULE_LEVEL flag means that we are currently
+				 * loading a table by executing it as a control method.
+				 * However, if we encounter an error while loading the table,
+				 * we need to keep trying to load the table rather than
+				 * aborting the table load (setting the status to AE_OK
+				 * continues the table load). If we get a failure at this
+				 * point, it means that the dispatcher got an error while
+				 * processing Op (most likely an AML operand error) or a
+				 * control method was called from module level and the
+				 * dispatcher returned AE_CTRL_TRANSFER. In the latter case,
+				 * leave the status alone, there's nothing wrong with it.
 				 */
 				status = AE_OK;
 			}